Coupling between surface- and ground-carbon cycling delineated by millifluidics: Implications for soil respiration in a changing environmentÂ
The respiratory release of carbon dioxide (CO2) from the Earth’s soil into the atmosphere is a major, yet poorly understood, flux in the global carbon cycle. Understanding soil respiration sensitivity to elevated atmospheric CO2 (eCO2) and/or climatic warming remains one of the key sources of uncertainty in projecting terrestrial carbon balance and likely future shifts in the global climate. This study aims to deepen our mechanistic understanding of hidden mechanisms neither accounted for by large-scale Earth system models nor readily quantified by field experiments. We specifically explore the role of leaf-level response to eCO2 and/or temperature in regulating soil moisture (water saving effects) and the resulting impacts on CO2 release from soil due to root and rhizomicrobial respiration.
Over the course of this project, students have the opportunity to carry out some of the following tasks as part of their Master thesis:
(1) Design and fabrication of millifluidic setups resembling natural soil with microbial habitat subject to various water saturation conditions
(2) Perform experiments to visualize spatio-temporal distribution of soil water and subsurface O2 and/or CO2 gas concentrations (i.e., soil respiration hot spots) in response to changes in environmental conditions
(3) Develop a numerical model and perform simulations to study the flow field and transport through the micromodel
(4) Develop an analytical model to parametrize carbon balance dynamics under prescribed environmental conditions and determine whether (and how) the whole system could be maintained as a carbon sink
For more information, contact Dr. Erfan Haghighi (erfan.haghighi@eawag.ch) or Dr. Joaquin Jimenez-Martinez (jjimenez@ethz.ch).